Many methods of securing and coding data which are marked on data supports are known, including distribution or rearrangement and/or scrambling of data, in such a way that the succession of the data is modified so that the text cannot be decoded entirely without knowledge of the rearrangement code. However, this method is as safe as the data rearrangement code can be maintained secret. There is an important need of marking documents and items with automatically readable data in unintelligible manner. If depends to a large extent from the security against falsification of these data whether the system concerned is suitable for releasing events having legal and/or financial consequences. Examples for use of such data supports are cheque cards which are inserted into automatic distributors or automatic money distributors to release the delivery of wares or money, documents such as passports or stocks, which may be automatically read and checked for authenticity etc. With the known methods by thorough studying a plurality of various data supports, the rules of coding the data may be discovered. As soon as these rules are no more secret, the entire coding is practically without any value because data supports may be falsified by non-authorized persons.